Effects of Coffee Intake on Oxidative Stress During Aging-related Alterations in Periodontal Tissue.

BACKGROUND/AIM: The purpose of this study was to determine the anti-aging effects of coffee intake on oxidative stress in rat periodontal tissue and alveolar bone loss. MATERIALS AND METHODS: Male Fischer 344 rats (8 weeks old) were randomized to four groups; the baseline group immediately sacrificed, the control group fed with normal powdered food for 8 weeks, and the experimental groups fed with powdered food containing 0.62% or 1.36% coffee components for 8 weeks. RESULTS: Alveolar bone loss and gingival level of 8-hydroxydeoxyguanosine were significantly lower in the 1.36% coffee group than in the control group. Nuclear factor erythroid 2-related factor 2 translocation to the nucleus was significantly higher in the 1.36% coffee group than in the control group. CONCLUSION: Continuous intake of 1.36% coffee could prevent age-related oxidative stress in the periodontal tissue and alveolar bone loss, possibly by up-regulating the Nrf2 signaling pathway.

Topical application of ointment containing 0.5% green tea catechins suppresses tongue oxidative stress in 5-fluorouracil administered rats.

OBJECTIVE: The purpose of this study was to investigate the preventive effects of topical application of green tea catechins on tongue oxidative stress induced by 5-fluorouracil (5-FU) administration in rats. DESIGN: Male Wistar rats (n=28, 8 weeks old) were divided into four groups of seven rats each: a negative control group (saline administration and application of ointment without green tea catechins), a positive control group (5-FU administration and application of ointment without green tea catechins), and two experimental groups (5-FU administration and application of ointment containing 0.1% or 0.5% green tea catechins). Topical application of each ointment to the ventral surface of the tongue was performed once a day for 5days. The level of 8-hydroxydeoxyguanosine (8-OHdG) was determined to evaluate oxidative stress. Fluorescence staining was also performed to confirm nuclear factor erythroid 2-related factor 2 (Nrf2) translocation to the nucleus. RESULTS: After the experimental period, the ratios of 8-OHdG-positive cells in the ventral tongue tissue were higher in the positive control group than in the negative control group (P<0.05). On the other hand, those in the 0.5% green tea catechin group, but not in the 0.1% green tea catechin group, were lower than the positive control group (P<0.05). In addition, Nrf2 translocation to the nucleus was greater in the 0.5% green tea catechin group than in the positive control group (P<0.05). CONCLUSIONS: Topical application of ointment containing 0.5% green tea catechins could prevent tongue oxidative stress in 5-FU administered rats, via up-regulation of the Nrf2 signaling pathway.

Severe periodontitis is inversely associated with coffee consumption in the maintenance phase of periodontal treatment.

This cross-sectional study addressed the relationship between coffee consumption and periodontitis in patients during the maintenance phase of periodontal treatment. A total of 414 periodontitis patients in the maintenance phase of periodontal treatment completed a questionnaire including items related to coffee intake and underwent periodontal examination. Logistic regression analysis showed that presence of moderate/severe periodontitis was correlated with presence of hypertension (Odds Ratio (OR) = 1.99, p < 0.05), smoking (former, OR = 5.63, p < 0.01; current, OR = 6.81, p = 0.076), number of teeth present (OR = 0.89, p < 0.001), plaque control record ≥20% (OR = 1.88, p < 0.05), and duration of maintenance phase (OR = 1.07, p < 0.01). On the other hand, presence of severe periodontitis was correlated with smoking (former, OR = 1.35, p = 0.501; current, OR = 3.98, p < 0.05), coffee consumption (≥1 cup/day, OR = 0.55, p < 0.05), number of teeth present (OR = 0.95, p < 0.05), and bleeding on probing ≥ 20% (OR = 3.67, p < 0.001). There appears to be an inverse association between coffee consumption (≥1 cup/day) and prevalence of severe periodontitis in the maintenance phase of periodontal treatment.

Anti-ageing effects of dentifrices containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) on gingival collagen degradation in rats.

OBJECTIVE: Previous studies have demonstrated the relationship between ageing and oxidative stress. In this study, we examined the effects of topical application of a dentifrice containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) to the gingival surface on gingival collagen degradation in rats. DESIGN: Fischer 344 male rats (4 or 8 months old) were divided into two groups: experimental group and control group. Tomarina® (the experimental group) or control dentifrice (the control group) was applied 5 days per week for 2 months. RESULTS: In the control group, gingival collagen density decreased with ageing. In the experimental group, the collagen density did not change with ageing, and was greater than that in the control group at 10 months of age (p < 0.0083). In addition, the control group showed an increase in serum oxidative stress with ageing. The experimental group also showed increased serum oxidative stress, but the value was lower than the control group at 10 months of age (p < 0.0083). Furthermore, low expressions of protein oxidative damage in the periodontal tissue were observed in the experimental group, compared to the control group at 6 months and 10 months. CONCLUSION: These findings indicate that Tomarina® might suppress the effects of ageing on gingival collagen degradation, by decreasing oxidative stress in the rat model.

Supplementation of broccoli or Bifidobacterium longum-fermented broccoli suppresses serum lipid peroxidation and osteoclast differentiation on alveolar bone surface in rats fed a high-cholesterol diet.

High-cholesterol diet enhances osteoclastic activity on alveolar bone by increasing serum lipid peroxidation. We hypothesized that supplementation with dietary antioxidants, such as found in broccoli and its fermented products, might suppress increases in serum lipid peroxidation, contributing to the inhibition of osteoclastic activity after high-cholesterol diet intake. The purpose of the present study was to investigate the effects of broccoli and fermented broccoli consumption on serum lipid peroxidation and osteoclast differentiation in alveolar bone of rats fed a high-cholesterol diet. In this 12-week study, rats were divided into 4 groups (n = 6/group): a control group (fed regular diet) and 3 experimental groups (fed a high-cholesterol [1% wt/wt] diet, or a high-cholesterol diet supplemented with either broccoli powder [5% wt/wt] or Bifidobacterium longum-fermented broccoli powder [5% wt/wt]). Serum hexanoyl-lysine (HEL) levels were measured as a parameter of lipid peroxidation. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts in alveolar bone was enumerated to evaluate osteoclast differentiation. When compared with regular diet, the high-cholesterol diet increased serum HEL levels and resulted in a higher number of TRAP-positive osteoclasts at 12 weeks. The high-cholesterol diet supplemented with broccoli or B. longum-fermented broccoli showed lower levels of serum HEL and fewer TRAP-positive osteoclasts than the high-cholesterol diet at 12 weeks. In conclusion, consumption of broccoli, or its fermented product, inhibited the effects of a high-cholesterol diet on osteoclast differentiation in rat alveolar bone by suppressing serum lipid peroxidation.

Hydrogen-rich water attenuates experimental periodontitis in a rat model.

AIM: Reactive oxygen species (ROS) contribute to the development of periodontitis. As molecular hydrogen can act as a scavenger of ROS, we examined the effects of treatment with hydrogen-rich water on a rat model of periodontitis. MATERIAL & METHODS: A ligature was placed around the maxillary molars for 4 weeks to induce periodontitis, and the animals were given drinking water with or without hydrogen-rich water. RESULTS: The rats with periodontitis which were treated with pure water showed a time-dependent increase in serum ROS level. Compared with the rats without periodontitis, the periodontitis-induced rats which were given pure water also showed polymorphonuclear leucocyte infiltration and alveolar bone loss at 4 weeks. Hydrogen-rich water intake inhibited an increase in serum ROS level and lowered expression of 8-hydroxydeoxyguanosine and nitrotyrosine in the periodontal tissue at 4 weeks. Such conditions prevented polymorphonuclear leucocyte infiltration and osteoclast differentiation following periodontitis progression. Furthermore, inflammatory signalling pathways, such as mitogen-activated protein kinases, were less activated in periodontal lesions from hydrogen-rich water-treated rats as compared with pure water-treated rats. CONCLUSION: Consuming hydrogen-rich water might be beneficial in suppressing periodontitis progression by decreasing gingival oxidative stress.

Supplementation of green tea catechins in dentifrices suppresses gingival oxidative stress and periodontal inflammation.

OBJECTIVE: this study examined the effects of a dentifrice containing green tea catechins on gingival oxidative stress and periodontal inflammation using a rat model. DESIGN: twenty-four male Wister rats were randomly divided into four groups. The first group (Control group) received no treatment for 8 weeks. Periodontal inflammation was induced in the second group for 8 weeks. Periodontal inflammation was induced in the last two groups for 8 weeks and dentifrices with or without green tea catechins were topically applied to the gingival sulcus daily for 4 weeks prior to the end of the experimental period. RESULTS: rats that had experimental periodontal inflammation showed apical migration of the junctional epithelium, alveolar bone loss and inflammatory cell infiltration in the connective tissue subjacent to the junctional epithelium at 8 weeks, whilst the control group showed no pathologic changes. Topical application of a green tea catechin-containing dentifrice reduced inflammatory cell infiltration in the periodontal lesions to a greater degree than the control dentifrice at 8 weeks. The gingiva in which green tea catechin-containing dentifrice was applied also showed a lower level of expression of hexanoyl-lysine (a marker of lipid peroxidation), nitrotyrosine (a marker of oxidative protein damage), and tumour necrosis factor-α (an indicator of pro-inflammatory cytokines) at 8 weeks compared to gingiva in which the control dentifrice was applied. CONCLUSIONS: adding green tea catechins to a dentifrice may contribute to prevention of periodontal inflammation by decreasing gingival oxidative stress and expression of pro-inflammatory cytokines.

Vitamin C intake inhibits serum lipid peroxidation and osteoclast differentiation on alveolar bone in rats fed on a high-cholesterol diet.

OBJECTIVE: A high-cholesterol diet stimulates osteoclast differentiation, which may be induced by increased serum lipid peroxidation. The inhibition of serum lipid peroxidation by vitamin C may offer beneficial effects on osteoclast differentiation including increased expression of receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) and NF-kappaB. This study investigated the effects of vitamin C intake on RANKL and NF-kappaB expression in periodontal tissue of rats fed a high-cholesterol diet. DESIGN: Twenty-four rats (8 weeks old) were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high-cholesterol diet supplemented with 0, 1 and 2 g/l vitamin C/day) in this 12-week study. Vitamin C was provided by its addition to drinking water. As an index of serum lipid peroxidation, hexanoyl-lysine (HEL) level was determined by a competitive enzyme-linked immunosorbent assay method. Immunohistological analysis was performed to evaluate RANKL and NF-kappaB expression on the alveolar bone surface. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts was also counted. RESULTS: Feeding a high-cholesterol diet increased not only the serum HEL level but also the number of TRAP-positive osteoclasts on the alveolar bone surface, with an increase in RANKL and NF-kappaB expression on alveolar bone surface. Intake of vitamin C reduced the serum HEL level and osteoclast differentiation, with decreasing RANKL and NF-kappaB expression. CONCLUSIONS: Vitamin C intake could suppress osteoclast differentiation, including RANKL and NF-kappaB expression on the alveolar bone surface, by decreasing serum lipid peroxidation in rats fed a high-cholesterol diet.

Oral administration of vitamin C prevents alveolar bone resorption induced by high dietary cholesterol in rats.

BACKGROUND: A high-cholesterol diet stimulates alveolar bone resorption, which may be induced via tissue oxidative damage. Vitamin C reduces tissue oxidative damage by neutralizing free radicals and scavenging hydroxyl radicals, and its antioxidant effect may offer the clinical benefit of preventing alveolar bone resorption in cases of hyperlipidemia. We examined whether vitamin C could suppress alveolar bone resorption in rats fed a high-cholesterol diet. METHODS: In this 12-week study, rats were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high-cholesterol diet supplemented with 0, 1, or 2 g/l vitamin C). Vitamin C was provided by adding it to the drinking water. The bone mineral density of the alveolar bone was analyzed by microcomputerized tomography. As an index of tissue oxidative damage, the 8-hydroxydeoxyguanosine level in the periodontal tissue was determined using a competitive enzyme-linked immunosorbent assay. RESULTS: Hyperlipidemia, induced by a high-cholesterol diet, decreased rat alveolar bone density and increased the number of tartrate-resistant acid phosphatase-positive osteoclasts. The expression of 8-hydroxydeoxyguanosine was upregulated in the periodontal tissues. Intake of vitamin C reduced the effect of a high-cholesterol diet on alveolar bone density and osteoclast differentiation and decreased periodontal 8-hydroxydeoxyguanosine expression. CONCLUSION: In the rat model, vitamin C suppressed alveolar bone resorption, induced by high dietary cholesterol, by decreasing the oxidative damage of periodontal tissue.